Discussing the Polish holiday of Dyngus Day Tuesday, Cooper, 44, dissolved into uncontrollable giggles when he told viewers about the day's celebratory events, which include girls striking boys with pussy willow branches. Watch the clip here.

"It's really so stupid," Cooper said during his giggle fit, referring to the fact that he couldn't stop laughing. The Kosciuszko Foundation -- which works to promote cultural exchange between the U.S. and Poland -- thought he was referring to the actual holiday, which is celebrated to mark the end of Lent, and issued a statement slamming the CNN host.

"Would Anderson Cooper dare make fun of the Islamic holiday Id al-Fitr, in which Muslims spend three days celebrating their month-long fast?" the organization's president, Alex Storozynski, said in a statement to the New York Daily News.

"Just learned some groups believe I called Dyngus Day 'so stupid' in RidicuList. I didn't. I was saying my giggling fit was 'so stupid.' Genuinely sorry if I offended anyone,'" the journalist clarified on Twitter, adding that the holiday "sounds like a fun celebration."